The invention relates in general to means for determining an open circuit and, in particular, to determining an open ground connection existing between a power source and a movable machine connected with the power source by means of a flexible cable.
Current methods for providing ground fault and open ground cable connections are disclosed within U.S. Pat. Nos. 3,671,856; 3,710,240; 3,895,264; 3,909,712; 3,911,358; 3,934,176; 3,938,006; 3,995,200, 4,041,381 and 4,075,675. The aforementioned patents disclose complex electronic circuitry and, in some cases, require three-phase conductors which include at least one ground conductor.
One currently employed power connecting cable utilizes three equal-sized phase conductors and three equal-sized ground conductors. Another power connecting cable contains two equal-sized ground conductors and a smaller diameter pilot wire conductor along with the three equal-sized phase conductors.
The ground connection monitor of the invention operates with both types of connecting cables for both determining the presence of an open ground connection as well as for determining the location of the open connection along the cable extent.